Die Casting Aluminum Alloys for Heat-Dissipating Plates

ABSTRACT

Provided is an aluminum alloy, and particularly, a die casting aluminum alloy for a heat sink, which includes 0.01 to 0.5 wt % of Cu, 0.3 to 0.6 wt % of Fe, 1.0 to 1.5 wt % of Si, and thus may enhance heat dissipation and castability.

TECHNICAL FIELD

The present invention relates to an aluminum alloy, and particularly, toa die casting aluminum alloy for a heat sink, which includes 0.01 to 0.5wt % of Cu, 0.3 to 0.6 wt % of Fe, and 1.0 to 1.5 wt % of Si, and thuscan simultaneously enhance heat dissipation and castability.

BACKGROUND ART

Generally, a heat sink part for a car audio is now manufactured using anAl—Si—Cu-based alloy through die casting.

Since such a heat sink part is manufactured of an alloy having excellentcastability and low heat dissipation, an audio part can be degraded inheat dissipation.

To solve such a problem, excellent industrial pure aluminum havingexcellent heat dissipation is suggested.

The pure aluminum had an excellent heat dissipation characteristic (234W/mK), but had defects after die casting.

In addition, to solve this problem, an Al—Si—Cu-based die casting alloy,an ALDC 12 species, which has excellent fluidity, was provided, but theALDC 12 species had low heat dissipation (96 W/mK).

DISCLOSURE Technical Field

The present invention is directed to providing a die casting aluminumalloy for a heat sink, which has excellent heat dissipation andcastability.

Technical Solution

One aspect of the present invention provides a die casting aluminumalloy for a heat sink including 0.01 to 0.5 wt % of Cu, 0.3 to 0.6 wt %of Fe, and 1.0 to 1.5 wt % of Si.

Here, the aluminum alloy may further include 0.0035 to 0.01 wt % of Mn.

In addition, the aluminum alloy may further include 0.01 to 0.5 wt % ofCu, and 0.3 to 0.6 wt % of Fe.

Advantageous Effects

According to the present invention, heat dissipation and castability canbe enhanced.

DESCRIPTION OF DRAWINGS

FIG. 1 is a conceptual diagram of an apparatus for testing fluidity ofan aluminum alloy.

FIG. 2 is an image of a fluidity test conducted by the apparatus for afluidity test.

FIG. 3 is a graph showing test results obtained using the apparatus forthe fluidity test.

FIGS. 4 to 6 are images of heat sinks casted using aluminum alloysaccording to the present invention.

FIG. 7 is a graph showing heat dissipation of the aluminum alloysaccording to the present invention.

FIG. 8 is an image of an aluminum alloy tissue of the present invention.

MODES OF INVENTION

Before a variety of Examples of the present invention will be describedin detail, it can be noted that applications are not limited to detaileddescriptions of a configuration and arrangements of components to bedescribed in the detailed description or illustrated in the drawings.

The present invention will be implemented by other Examples, andperformed by a variety of methods.

In addition, the expressions and phrases used for the terms indicatingdirections of an apparatus or factor (e.g., “front,” “back,” “up,”“down,” “top,” “bottom,” “left,” “right,” “lateral,” etc.) are merelyused to simplify the description of the present invention, and it can benoted that it does not mean that the related apparatuses or factorssimply have a specific directions.

Hereinafter, Examples of the present invention will be described indetail with reference to the following drawings. Beforehand,terminologies used in the specification and claims should not beconstrued as conventional or literal meanings, but should be construedas meanings and concepts corresponding to the technical idea of thepresent invention based on the principle in which the inventor cansuitably define the concept of a term to explain his own invention bythe most preferable method.

Accordingly, the configurations illustrated in Examples and the drawingsof the specification are merely the most preferable Example of thepresent invention, and do not represent the entire technical ideas ofthe present invention. For this reason, it should be understood thatthere are various equivalents and modifications that can replace theconfigurations at the time of application.

The present invention relates to a die casting aluminum alloy for a heatsink including includes 0.01 to 0.5 wt % of Cu, 0.3 to 0.6 wt % of Fe,and 1.0 to 1.5 wt % of Si to simultaneously enhance heat dissipation andcasting characteristics as described above.

Here, the aluminum alloy of the present invention may further include0.0035 to 0.01 wt % of Mn having an effect on thermal conductivity.

In addition, the aluminum alloy may further include 0.0001 to 0.001 wt %of Mg.

Hereinafter, the aluminum alloy of the present invention described abovewill be compared with Comparative Examples.

TABLE 1 Comparison of Comparative Examples with Examples Compositionratio (wt %) No. Si Fe Cu Mg Mn Al Comparative 1.058 0.572 1.025 0.00050.0032 Bal. Example 1 Comparative 1.465 0.589 0.543 0.0009 0.0034 Bal.Example 2 Comparative 0.524 0.612 1.048 0.0004 0.0031 Bal. Example 3Example 1 0.992 0.594 0.052 0.0006 0.0041 Bal. Example2 1.488 0.3100.048 0.003 0.0038 Bal.

Fluidity Test

A fluidity test was performed to evaluate castability.

For the fluidity test, as shown in FIG. 1, an apparatus for a fluiditytest 100 having a sprue 120 formed in the center of a disc-type mainbody 110 was used.

Here, from the sprue 120 of the main body 110, six linear flow channels130 spaced certain angles were formed.

Each of the fluid channels 130 had a width W of 5 mm, and a length L of200 mm.

However, the depths t were respectively 1 mm, 2 mm, 3 mm, 4 mm, 5 mm,and 6 mm.

An alloy corresponding to Comparative Example 1, Comparative Example 2,Comparative Example 3, Example 1 or Example 2 was input to the sprue 120of the test apparatus 100.

FIG. 2A shows the alloy corresponding to Comparative Example 1, FIG. 2Bshows the alloy corresponding to Comparative Example 2, FIG. 2C showsComparative Example 3, FIG. 2D shows the alloy corresponding to Example1, and FIG. 2E shows the alloy corresponding to Example 2.

FIG. 3 shows flow distances of the alloys for respective channels 130,which are measured by the test apparatus 100.

In other word, a horizontal axis of FIG. 3 shows Comparative Example 1,Comparative Example 2, Comparative Example 3, Example 1, and Example 2,and a vertical axis thereof shows the flow distances of the alloys.

As shown in FIG. 3, the flow distances of Example 1, Example 2,Comparative Example 1 and Comparative Example 2 are 720 mm or more, andit can be confirmed that the alloys had good castability.

It can be noted that, for the sake of the castability, Si should beincluded in an amount of 1.0 wt % or more.

Test for Confirming Generation of Casting Defects

As another aspect of the castability test, a test was performed toconfirm whether defects were generated in a product produced by casting.

The casting was performed in the shape of a heat sink, as shown in FIG.4.

In addition, conditions for an apparatus for die casting are shown inTable 2.

TABLE 2 Condition for die casting Clamping force Injection forceAccumulator 1500 kN 490 kN 15.5 Mpa Length of sleeve Diameter of plungerPacking factor 425 mm Φ60 32%

In addition, die casting injection conditions are shown in Table 3.

TABLE 3 Injection conditions Plunger position (mm) Plunger speed (m/s)step 1: 120 0.2 step 2: 320 0.8 step 3: 380 1.2 step 4: 410 2.5 step 5:425 2.5

In Comparative Example 1, by the result of casting under the aboveconditions, defects were generated in a part represented by a circle inFIG. 5A.

In Comparative Examples 2 and 3, defects were also generated in theparts shown in a circle, respectively.

Such defects are hot tearing defects generated in casting, andrepresentative images of the defects are FIGS. 5D and 5E.

As noted from the test, in Comparative Examples 1, 2 and 3, theabove-described defects were generated, but in Examples 1 and 2, thedefects were not generated, and excellent castability could beconfirmed.

In addition, as confirmed from FIGS. 6A to 6E, in Comparative Examples(FIG. 6A), Comparative Example 2 (FIG. 6B), and Comparative Example 3(FIG. 6C), defects were not observed, but in Example 1 (FIG. 6D) andExample 2 (FIG. 6E), defects were not observed.

Accordingly, it was noted that the alloys formed in the compositionsdescribed in Examples 1 and 2 had excellent castability.

Heat Dissipation Test

For a heat dissipation test, thermal conductivity was analyzed byforming disc-type samples having a diameter of 12.7 mm and a thicknessof 2 mm using the alloys manufactured in Comparative Example 2, Examples1 and 2.

As shown in FIG. 7, the heat conductivities were approximately 150 W/mkin Comparative Example 2, 198.472 W/mK in Example 1, and 185.999 W/mK inExample 2, respectively.

In other words, it can be noted that the alloys of the present inventionhad considerably higher heat conductivities than that of the ALDC 12,which is 96.2 W/mK, and thus had higher heat dissipation.

As described above, it can be noted that the alloys having thecompositions described in Examples 1 and 2 have excellent castabilityand heat dissipation, and can manufacture a heat sink which is easilycasted and has good heat dissipating performance using such alloys.

DESCRIPTION OF REFERENCE NUMERALS

100: Apparatus for fluidity test/110: Main body

1. A die casting aluminum alloy for a heat sink, comprising: Cu in anamount of 0.01 to 0.5 wt %, Fe in an amount of 0.3 to 0.6 wt %, and Siin an amount of 1.0 to 1.5 wt %.
 2. The alloy according to claim 1,further comprising: Mn in an amount of 0.0035 to 0.01 wt %.
 3. The alloyaccording to claim 1, further comprising: Mg in an amount of 0.0001 to0.001 wt %.